The evolution of a mountain bike: Integrated Di2 cockpit (Build 9)

XTR Di2 gets even more integrated

Thanks to Shimano MTB, I received a set of PRO Tharsis Trail Di2 riser bars (800mm wide, 20mm rise, 8º back sweep and 4º up sweep) and PRO Tharsis Trail Stem (45mm x 0º rise). The stem comes with, what Shimano are calling, the “BTR expander” which is a little bit like a Hope HED Doctor combined with a Di2 battery holder. This allows the cockpit to become totally integrated.



There is a very clever channel for the shifter e-tube to sit in, which then runs inside the grip and the bar to the stem. The battery is fully enclosed in the steerer with an e-tube running through the stem to the IMG_0149Digital Control. There is something very cool about a well built integrated system.


Shimano, as always, have done their homework and the up and back sweep on the bar is spot on.

At 6’2″ tall, with a relatively long reach, I trimmed the bars to 780mm after some serious measurements on a bar bell at the gym. This is the best way to determine the width of a bar to optimise your body geometry and strength; another way is to assume one’s strongest push up position and measure the distance between the hands. I prefer the bar bell method as it is easier to get a full width measurement with the hands gripping a bar that is a similar diameter to a grip.

Leaving the handlebar at 780mm is wider than I have been running the bar on my trail bike but I thought I would experiment for three months and see if it works or not. Note that the shape of the Ergon GE1 grips mean that the total width ends up being close to 790mm.



I press fit, by hand, a plain hand basin plug to the bottom of the steerer to further proof the battery area against water, mud and dust ingress. It has happily stayed there for the last three months.




This is the list of parts, to save other people time , that I used to integrate the cockpit:

PRO Tharsis Trail Di2 Carbon Handle bar (800mm wide, 20mm rise, 8º back sweep and 4º up sweep).

PRO Tharsis Trail Stem Di2 (45mm x 0º rise).

EW-SD50L 700mm e-tube (SW-M9050R Firebolt shifter to SC-M9050 Digital Display Unit; through the handle bar and stem).

EW-SD50L 400mm e-tube (SM-BTR2A Internal Battery to SC-M9050 Digital Display Unit; through the stem).

32mm hand basin plug trimmed flat (or stopper if you are an American).

As previously discussed I use a EW-SD50L 950mm e-tube to connect the Digital Controller (through the frame) to the SM-EWW01 Wireless Transmitter and then a EW-SD50L 750mm e-tube to connect to the RD-M9050GS Rear Derailleur.

Simple really, but having spent time poring over Shimano’s user manuals (which are heavily focused on XC style set up including electronic lockout for Fox suspension) I know that this is the simplest explanation for a 1 x 11 system.